Projecting, measuring, and gauging device



' May 23, 1950 4 F. POLK PROJECTINGI, MEASURING, AND GAUGING DEVICE Filed Dec. 3, 1948 i! Elise-iii...

INVENTOR- 41 47 BY Patented May 23, 1950 PROJEGTING,

MEASURING, AND GAUGING DEVICE Louis F. Polk, Dayton, Ohio, assignor it The Sheflield Corporation, Dayton, Ohio, a corporation of Ohio Application December 3, 1948, Serial No. 63,299

3 Claims.

a. This invention relates to measuring instruments and more particularly to dimension measuring instrumentsin which a dimension is measured by means of fluid leakagetaking place between the object or work and a work head.

. One object of the invention is the provision of a dimensionvmeasuring instrument of the character mentioned including an optical system having a scale on which indications are produced in accordance with the position of a member operated by a fluid pressure responsive device which in turn is controlled in accordance with the fluid leakage taking place between the object and the work head, the entire device working without friction due to the elimination of articulated connections and measuring the dimension of the work or object without physical contact with the object.

Another object of the invention is the provision of a dimension measuring instrument having a pressure responsive tube which flexes in accordance with the pressure supplied to'the tube, such pressure being governed by the amount of leakage taking place at the work, the pressure responsive tube being fixed to a target arm operable in the path of a light beam so that an actual indication of the size or dimension is precisely measured on anindicating scale visible to the operator.

Other objects and advantages of the invention will be apparent from the following description,

the appended claims and the accompanying drawing, in which 1 is a vertical sectional view taken centrally through a measuring instrument embodying the present invention; and

Fig. 2 is a vertical section on the line 22 of Fig. 1.

Referring more particularly to the drawing in which the same reference numerals have been applied to like parts in the difierent views, the dimension measuring instrument of the present invention embodies a housing formed by an upstanding back plate ln fixed by means of screws II to a front cover [2 which also forms a base portion [3. Fixed on the back plate by means of screws I4 is a bracket IS the forward portion of which extends through a hole l6 in the cover l2, where it is attached by means of a coupling I! to a flexible tube I8 leading to a work engaging head l9 adapted for telescopic interengagement with the work. As shown, the head I9 is a plug or spindle adapted to measure the inside diameter of a hole in an object or workpiece, although it will be obvious that the shape and size of the work a 2 head [9 is determined by the particular object to be gauged. v V,

The work head I9 is provided with a pair of diametrically opposed gauging orifices 20 through which air or other fluid supplied under pressure through the tube 18 flows, the amount of the flow being dependent upon the clearance between the outer surface of the gauging orifices and the workpiece surface gauged. In pneumatic gauges of this character, there is no physical contact be- *tween the work and the gauging orifices and the dimension may be gauged, therefore, with no possibility of marring or scratching the workpiece. Air under pressure is supplied through a pipe ii to a pressure regulating valve 22 carried by the bracket 85. The pressure controlled fluid then flows through a manually adjustable restrictor valve 24 into'a passage 23 in the bracket, the valve 24 producing a drop in pressure so the pressure of the air or other fluid inthe passage 25 is depend- =-ent upon the amount of leakage taking place at the hollow tube 26, the arm 28 is positioned as'i'ndicated at Fig. 2, but when the tube is subjected to pressure, asunder operating conditions, the'free end' of the tube, to a small degree,'has an'unwinding movement, thus swinging the arm counter-clockwise as viewed in that figure to an extent dependent upon the pressure in the tube which in turn is dependent upon the amount of leakage taking place at the work. I

The upper end of the arm 28 carries a target portion 29 having a light intercepting edge 30. This target portion is arranged in the path of a light beam that travels from a lamp 3| through condensing lens 32 and an objective lens 33 to a measuring scale 34 held on a supporting plate 35 which is carried by bracket IS. The lamp and lens system are carried by an upper bracket 3'! fixed by means of screws 38 on the back plate Hi. When the target is positioned as shown, it intercepts light to the measuring scale leaving the scale in shadow, but under operating conditions the edge 3!] permits illumination of a part of the scale and projects an image of the edge 30 on the scale giving a sharp shadow line or indication of the actual measurement of the workpiece. The scale is visible through a glass 39 arranged in an opening 40 through which the operator can inspect the measuring scale.

It will be obvious that in the emuewsrem;

from the workpiece through the fluid pressure system and through the -eptieaisystem-winch translates the results of theopti'ea'l systmihto an actual physical measurement, there are no sliding joints or pivots. Bothiigthegoptiealzand the fluid pressure parts operate withoutfriction and, consequently, without error caused 'bywear.

Extremely accurate and precise measurements 20 tamtriuszbefobtainewtoidetermineithe@actuahsize of the diameter or other dimension cliecked adue -to" the 'h-igh amplification factor s-ofa the instruement: and this Tis;accomplishedgaas ialreadyamentione'd; without requiring the application? oi-iphyz -siealspressuremon the workpiece.

i'while theformeot apparatusiherein described :constitutes a preferred embodiment/of atheiinmention; it is -.to he understood that 'thelinvention -is' not; limited. to; this precise. form;- of; apparatus,

za'andethat changes may be made therein without :departing from the scope of the invention, which isgdefined in the-.appendedclaims.

WVhatis.claimedisz, l. l .7 V

, 1. A measurin instrument of lithe. chara t sdescribed compris n asuppo m a measuringsce hand... a; l ht so rce nienntedi n sa dasup or i de sys em or jec in al ht beam mmgt rs urce to the sca e, a. movable memb r, havipea rest t o i n erpo edinthe pathpi helieh :1 beam betwe n t e sta e an lthe. i htv squr an producing an indication on the scale imaccgijdease w th, the q t pp f sa d memheria fl x su erre o i ee ent owe u portsei ss ment av n e ez be m l in .r s' o e l chahges in ,pres'sureiof said element, said. portion 11h iejae e iiqnitf ei em f ti t member in accordance, h the p'ressureapmemberrimaccordance?wit sureyapplledtdth b 4 2. A measuring instrument of the character described comprising a support, a measuring scale and a light source mounted on said support, a lens system for projecting a light beam from the source to the scale, an arm having a target portion interposed in the path of the light beam be- T-tweentthascaldand thli'htfibificaahd producirig an indication on the-scale irr accordance with the position of said arm, a flexible pressure-re 1 1'0 sponsive tube on said support said tube having a f novableend-fixedto said arm to position the targg'et portion in" accordance with the pressure applied to the tube, and means for connecting said it'ube to e? pressure supply and to a gauging leakage takes place between the gaiig'i'ngheafand the workpiece to vary the spressureeanpl e gat t tubep 3.,A measuring instrument of the character described comprising i an upright supporting plate, a measuring scale and a light source inounted on sa;id piategsaia-lens-a'system onrls'aid "plate foi'i proje'etingalightobeamefmonritheisomce -to the scalepaznrovtableimember havingsa target -i3br ti0n2intenposedkmathmpatii the-"light beam 25 between zthescalesand the light: ourcerandeproiducing amindications n theiscale irraaocordance -'with the position;ofasaid member a fiexiblespiTes- -"surearesponsive tubeiomsaidxplateysaid-stubehavhinge amonnectiom'toisaidcinemb m 9051 5. 0 gk --the-;-;pres u eai plie .z torithewtube, means on late ior suppl xing 1':'fl iund rvpressureeto;sa d e:

whi he lll sz fi lifl fiifiakfifi:P 4 et ge agau in -hea ,and-- -w s-p e toava ieih -i i ntw u -pe :JQY sa di-nlat ean i v e .njpp n'n manganeseis l i Q Ql-e-QQQL BQQQ said gauging head to said tube extending through a c1,. r0n rc r- ;LLQUI Q I QI I "'marimmosspnrm) iol ewine ef ane sia ebnree rdelnath fi1e,-pf,;.-this,patent: 

